Diversidade funcional das comunidades zooplanctônicas de um complexo lacustre neotropical

Abstract

Functional Diversity is a metric focused on measuring the multiple functions exerted by species on a ecosystem, analysed by variables named attributes or functional traits (e.g. body size, biovolume) which can represent their life histories. This metric is a complementary form to measure the diversity of communities, being possibly associated to other metrics of the same community such as taxonomic diversity measurements. The objectives of this work were verifying if Functional Diversity patterns existed in lagoons and if this metric corresponded to the already described taxonomic diversity patterns in which external lagoons to the Parque Estadual do Rio Doce (PERD) were found to have a higher number of species. We also seeked to analyse and compare possible patterns between the zooplankton species density and biovolume measurements in the PERD lagoons, and to explore possible relations of these metrics to environmental variables. Measurements were obtained from 17 lagoons of a lake complex, including lagoons external and internal to the PERD, during August of 2007 and February of 2008. 40 different environmental variables were analysed including amongst them variables related to: climate, riparian woodlands and land usage, biovolume, the population structure of algae, exotic fish presence, seasonality, light refraction and the coverage percentage of macrophyte; and 18 zooplanktonic species were analysed between copepods, rotifers and cladocerans (which contributed to at least 5% of the total species density of the 17 lagoons). For the functional diversity analysis 20 attributes were analysed (size, average biovolume, trophic positioning, feeding habits and escape response). In respect to functional diversity, the functional indexes followed a similar trend to the taxonomic indexes, displaying higher values in external lagoons and smallest values in the Gambazinho lagoon (most preserved). For the biovolume and density analysis, Cladocerans were demonstrated to be the most sensitive to environmental variables. Heterogeneity and seasonality were the most determining factors in the analysed variables, along with the presence of exotic fish species.